4 
THE CORNISH PUMPING ENGINE. 
available; and whence, after supplying wheels on a superior level, it was again 
conveyed, in a similar manner, to distant and lower ones. Even the water pumped 
up was frequently made to contribute to services of this kind, before being allowed 
to find its way into the sea. 
Up to somewhere about the year 1700, small wheels of 12 or 15 feet diameter 
were thought the best machinery for draining mines; and if one or two were in 
sufficient, more were applied, sometimes to the number of seven, all worked over 
each other by the same stream of water. But about the above-mentioned date, a 
certain Mr. John Costar, of Bristol, “who was particularly knowing in mechanics 
and hydraulics,” came into the county, and taught the natives an improvement by 
removing the small wheels, and substituting large ones of from 30 to 40 feet 
diameter in their stead. He applied these to many mines with success. 
7. But the paucity of running streams in the mining districts, necessarily the 
consequence of the form and nature of the country, rendered water power available, 
even with the aid of the ingenious contrivances above alluded to, in comparatively 
few situations; and in many of these it could only be used during a certain portion 
of the year; for in the dry season the supply became much diminished, and some 
times entirely failed. 
Moreover, as the mines were worked deeper, the influx of water was continually 
increasing; as was also the height to which it had to be raised; so that the power 
necessary to extract it was required to be increased in something like a duplicate 
ratio with the depth of the mine. 
This fixed a limit to the use of water power in all situations where the supply 
was not found in great abundance, and the consequence was, that at the early part 
of the last century, many of the mines in which this power was used had arrived at 
its limit, and were on the point of being abandoned; while the use of animal power 
to any great extent was out of the question, as its expense would have more than 
consumed all the profits yielded by the produce of the mine. 
How opportune then was it, that just at the approach of this crisis, the use of 
such a mighty agent as steam should be discovered, furnishing a power, not only 
vast and almost unlimited in capability, but independent of local circumstances, and 
at a cost sufficiently small to render it generally available. “ It should seem,” says 
Pryce, a Cornish historian of the last century, 3 “as if we had been led by the kind 
hand of Providence in this discovery; for as soon as we found out the ne plus ultra 
of the power of water, and the necessity of further improvements in hydraulics, a 
3 ‘ Mineralogia Cornubiensis : a Treatise on Minerals, Mines, and Mining, by William Pryce, M.D., of 
Redruth in Cornwall. London, 1778.’ Page 307.